Micropipette-based biomechanical nanotools on living cells

Abstract

Mechanobiology is an emerging field at the interface of biology and mechanics, investigating the roles of mechanical forces within biomolecules, organelles, cells, and tissues. As a highlight, the recent advances of micropipette-based aspiration assays and dynamic force spectroscopies such as biomembrane force probe (BFP) provide unprecedented mechanobiological insights with excellent live-cell compatibility. In their classic applications, these assays measure force-dependent ligand–receptor-binding kinetics, protein conformational changes, and cellular mechanical properties such as cortical tension and stiffness. In recent years, when combined with advanced microscopies in high spatial and temporal resolutions, these biomechanical nanotools enable characterization of receptor-mediated cell mechanosensing and subsequent organelle behaviors at single-cellular and molecular level. In this review, we summarize the latest developments of these assays for live-cell mechanobiology studies. We also provide perspectives on their future upgrades with multimodal integration and high-throughput capability.

Fluorescence-coupled micropipette aspiration assay to examine calcium mobilization caused by red blood cell mechanosensing

“…Compared to other methods, such as the tonicity assay, micropipette-based techniques are easier to assess and quantify mechanical stimuli and the mechanical properties of cells (Wang et al 2022b ), such as membrane tension using relevant physical models (Fig. 1 b) (Mierke 2021 ).…”

“…More recently, micropipette aspiration assays have been combined with fluorescent imaging which enables numerous live-cell mechanobiology studies, including nuclear remodeling (Swift et al 2013 ), ion channel mechanogating (Cox et al 2016 ), and receptor-mediated mechanosensing (Chen et al 2015 , 2019 ; Liu et al 2014 ). Such instrumental integration provided a direct approach to visualize single-cell mechanosensing (Wang et al 2022b ). Nevertheless, there is lack of technical study to head-to-head benchmark the efficacy of water vs. pneumatic apparatus and their distinct mechanical profiles of aspiration on cell mechanosensing (cf.…”

The N-terminal autoinhibitory module of the A1 domain in von Willebrand factor stabilizes the mechanosensor catch bond

“…The stiffness of the RBC ( k RBC ) can be determined by the radii of the orifice ( R p ), the probe bead ( R c ) and RBC ( R 0 ) when the aspirated tongue length ( L p ) of the RBC is equal to R p : 34,72 The pressure applied to the RBC is precisely controlled by our homemade manual water manometer so that the spring constant of the RBC can be modified to 0.3 pN nm −1 by adjusting the height difference between the water level in the reservoir and the tip of the micropipette. 34,73 As a result, the force applied to the probe bead can be interpreted via the deflection of the RBC. During each experiment cycle (Fig.…”

“…1a, top left). 1 In structure, each VWF monomer of 250 kDa consists of probe (BFP), 4,10,34 and optical tweezers (OT), 11,13,35 enabled the characterization of force-dependent VWF-GPIba binding kinetics at the molecular scale. To complement such biophysical studies, shear-dependent platelet perfusion assays were performed using microfluidics.…”

Insights into intercellular receptor-ligand binding kinetics in cell communication

“…Benefitting from the development of biomechanical techniques, researches on mechanobiology have leaped ahead in the past decades ( Su and Ju, 2018 ; Zhu et al, 2019a ; Wang et al, 2022 ). Biomechanical tools, such as traction force microscopy, micropillar array and DNA force probe, have definitely confirmed the existence of biomechanical forces actively exerted by single cells to their binding partners through receptor-ligand interactions ( Wang and Ha, 2013 ; Bashour et al, 2014 ; Liu et al, 2016 ; Colin-York et al, 2019 ; Ma et al, 2019 ).…”